Fasting is a medicine. But medicine, as beneficial as it is, becomes useless because of the inexperience of the user. He has to know the appropriate time that the medicine should be taken and the right amount of medicine and the condition of the body which is to take it, the weather conditions and the season of the year and the appropriate diet of the sick and many other things. If any of these things are overlooked, the medicine will do more harm than good. So, if one who is going to heal the body needs so much accuracy, when we care for the soul and are concerned about healing it from bad thoughts, it is necessary to examine and observe everything with every possible detail.